1. Field of the Invention
The present invention relates to an apparatus for supplying spout attachment bags, which is used to supply spout attachment bags each having a spout attachment opening formed at a corner thereof (thus can be called, “corner spout attachment bags”) to a spout attachment apparatus.
2. Description of the Related Art
Patent Document 1 (Japanese Patent No. 4566628) discloses supply of a spout (corner spout) to a spout attachment opening that is formed at a corner of a spout attachment bag (a bag to which a spout is to be attached) in a spout attachment apparatus. In this case, the bag is tilted (rotated along the bag plane) so that the spout attachment opening faces upward and is horizontal, and then the spout attachment bag is supplied in this state to the spout attachment apparatus.
Meanwhile, the applicant of the present patent application disclosed an apparatus for supplying spout attachment bags in Japanese Patent Application No. 2014-043864 (Japanese Patent Application Laid-Open (Kokai) No. 2015-168459). This supply apparatus supplies spout attachment bags each having a spout attachment opening formed at a corner to a spout attachment apparatus. This supply apparatus comprises a positioning device (6) that positions a spout attachment bag at a specific position in a horizontal orientation so that a spout attachment opening is facing forward, a rotary transfer device (5) that transfers a spout attachment bag to the positioning device (6) in a horizontal orientation in which the spout attachment opening is facing forward, and a transfer device (57) that transfers upward the spout attachment bag positioned by the positioning device and, in the course of this transfer, changes the spout attachment bag from the horizontal orientation to a vertical orientation so that the spout attachment opening faces upward and is horizontal. The reference numerals in parentheses above are the reference numbers of various devices disclosed in the drawings of the Japanese Patent Application No. 2014-043864 (Japanese Patent Application Laid-Open (Kokai) 2015-168459).
The rotary transfer device (5) includes a support shaft that is disposed vertically. This support shaft can be moved up and down and rotated and is further moved reciprocally along the transfer direction of the spout attachment bags. The rotary transfer device (5) further includes a suction member that is installed at a lower end of the support shaft and whose suction face faces downward. The rotational axis of the support shaft is always located in a reference plane (that is set on a single vertical plane); and a spout attachment bag positioned in a horizontal orientation at a specific position is picked up by the suction member, lifted upward, and then transferred while being kept in a horizontal orientation. The spout attachment bag is rotated by a specific angle along the bag plane in the course of (or during) this transfer. The spout attachment bag, at a specific position, is positioned so that the center line of the bag (a straight line that passes through the center in the width direction of the bag) is positioned in the reference plane, and the bag is rotated during this transfer, so that a perpendicular line passing through the center of the spout attachment opening is positioned in the reference plane. The bag is supplied in this state to the positioning device.
The positioning device described above includes a conveyor on which the supplied spout attachment bags are placed and which sends the bags forward, and it further includes a side edge stopper and a top edge stopper which are contacted by one side edge and the top edge, which are flanking the spout attachment opening of a spout attachment bag. The role of this positioning device is to position the distal end of a spout attachment bag and to reposition the perpendicular line passing through the center of the spout attachment opening in the reference plane. The side edge stopper and the top edge stopper are disposed so that the perpendicular line passing through the center of the spout attachment opening is positioned in the reference plane when the spout attachment bag on the conveyor are moved forward and has come to contact with the stoppers.
FIG. 10 (including part (a) and part (b)) shows a state in the positioning device in which a spout attachment bag 1 placed on the conveyor (not shown) is fed forward by the conveyor, and one side edge (which is sealed) 3 and the top edge 4 flanking the spout attachment opening 2 have come to contact with a side edge stopper 5 and a top edge stopper 6, respectively.
In the embodiment shown in the Japanese Patent Application No. 2014-043864 (Japanese Patent Application Laid-Open (Kokai) 2015-168459), a spout attachment bag whose corner is not cut (and thus no spout attachment opening has been formed) is supplied to the positioning device. This is because the step of cutting the corner is performed in the spout attachment apparatus. By contrast, the spout attachment bag 1 shown in FIG. 10 of the present application has its corner cut ahead of time in the bag production step, and the spout attachment bag 1 in which the spout attachment opening 2 has been formed is supplied to the positioning device.
Generally, cutting errors would occur when a corner of a spout attachment bag is cut in bag manufacturing steps. The cutting error referred to here is that in which the cut length (the length of the spout attachment opening 2) deviates from the reference value; and if such a cutting error occurs, as seen from FIG. 10, the position of the distal end (the spout attachment opening 2) of the spout attachment bag 1 positioned by the side edge stopper 5 and the top edge stopper 6 deviates from a reference position. In the example in FIG. 10, if the cut length L0 of the spout attachment bag 1 shown in part (a) of FIG. 10 is the reference value for the cut length, then the reference position is that which is indicated by the straight line P0 (hereinafter referred to as the reference position P0). Meanwhile, the cut length L of the spout attachment bag 1 shown in part (b) of FIG. 10 is somewhat longer than the above-mentioned reference value (L>L0), and therefore the position of the distal end (the spout attachment opening 2) of the spout attachment bag 1 is moved back by a distance of d1 from the reference position P0. Conversely, if the cut length L of the spout attachment bag 1 is shorter than the reference value (L<L0), then the position of the distal end (the spout attachment opening 2) of the spout attachment bag 1 is moved forward by a specific distance from the reference position P0.
If the position of the distal end (the spout attachment opening 2) of the spout attachment bag 1 deviates from the reference position P0, when that spout attachment bag 1 is supplied to a spout attachment apparatus and is gripped by grippers of the spout attachment apparatus, the height of the spout attachment opening 2 of that spout attachment bag 1 will deviate from the reference height and, as a result, the sealing position of the spout will be offset, which diminishes the appearance of the bag and can decrease the seal strength of the bag.
On the other hand, as shown in FIG. 11, if the positioning of the spout attachment bag 1 by the positioning device is performed by a distal end stopper 7 that is in contact with the distal end (the spout attachment opening 2) of the spout attachment bag 1 and the side edge stopper 5 that is in contact with the side edge 3, then no deviation will occur in the position of the distal end (the spout attachment opening 2) of the spout attachment bag 1 from the reference position. In this case, however, a problem that occurs is that a perpendicular line M passing through the center of the spout attachment opening 2 of the spout attachment bag 1 deviates from the reference plane. In the example of FIG. 11, the cut length L0 of the spout attachment bag 1 shown in part (a) of FIG. 11 is the reference value for length, in which it is assumed that the perpendicular line M passing through the center of the spout attachment opening 2 is positioned in the reference plane N. On the other hand, the cut length L of the spout attachment bag 1 shown in part (b) of FIG. 11 is somewhat shorter than the reference value (L<L0), and therefore the position of the perpendicular line M passing through the center of the spout attachment opening 2 of the positioned spout attachment bag 1 deviates by a distance d2 from the reference plane N.
If the position of the perpendicular line M passing through the center of the spout attachment opening 2 of the spout attachment bag 1 deviates from the reference plane N, when that spout attachment bag 1 is supplied to a spout attachment apparatus, the left and right grippers of the spout attachment apparatus may not be able to grip the bag properly, or the seal position of the spout may deviate from the center of the spout attachment opening 2. This can diminish the appearance of the bag and cause an imperfect seal, resulting in that the problem is more serious than when the position of the distal end (the spout attachment opening 2) of the spout attachment bag 1 deviates from the reference position P0.
When the spout attachment bag 1 is positioned by the side edge stopper 5 and the top edge stopper 6, even if the cut length of the spout attachment bag 1 should deviate from the reference value, substantially no deviation would occur for the position of the perpendicular line M passing through the center of the spout attachment opening 2 from the reference plane N.